When she was told that she had completed her job, she ripped off the necklace protecting her and burned in the sun.

Speaking to Entertainment Weekly, Plec hinted that Isobel killed herself because of her compulsion.

"I love that people debate it because I think it's actually fun to think of either way, but very deliberately we used the same language as in [season one, episode 15] with the guy that got hit by the bus," she said. "At the end of each of them, the person who's been compelling them says, 'Okay, you're done' and they say, 'I'm done' like they're grateful.

"So it's a compulsion like a suicide bomber. 'I have done the task that I was compelled to do, and now my reason for existence is over'. So we deliberately echoed that same language to imply that her death had been written in the cards by Klaus already."

Plec also suggested that Isobel's death had a big impact on Elena (Nina Dobrev), saying: "Why I loved Isobel taking [Elena] to the cemetery and finding a work-around her compulsion, where she's not allowed to say anything, is she was able to apologize for not being a good mother and to give Elena that before she did what she had to do. If anything, Isobel in death was able to give Elena a tiny bit of closure."

The Vampire Diaries airs on Thursdays at 8/7c on The CW in the US and on Tuesdays at 9pm on ITV2 in the UK.